s2soonap1

Hey guys,
I just traded my 135i for an 03 s2k and on my first drive, the back rotated like no car I've ever had before, I think I lost traction slightly but how quick it happened and how twitchy the back end is scaring me a lot. its like any bump could unsettle it.
Even though I am new to this forum, I'm not new to forums and I do research before I come out and ask questions. After research I saw a lot of suggesting to change the ap1 rear sway bar to the ap2 which should bolt in place.
I have an idea that I didn't see anyone mention that I'm hoping I'd get some help from you guys on whether it should work or not.
What if I put all season tires on the front 215/40/17 and ultra high performance summer tires on the back (I'm thinking mpss or something similar 255/40/17) my logic behind that, is that way front tires would always lose grip before the rear tires, and even though I might not have the most grip on the street the car would theoretically under-steer before it over-steers right? or is that a dumb idea?

Manga_Spawn

What is on the car now? The sway bar is likely cheaper than the tires and it is a pretty easy install but it the tires are crap then that is the first issue I would address. I would also have the alignment checked to make sure nothing is way off causing the car to behave poorly. AP1's are more tail happy due to the suspension and the narrower tires but it sounds like more than the usual twitchiness of the AP1.

I personally wouldn't run 2 totally different tires as it can ruin what is and should be a great handling car. You also have to take into account different road conditions ie if it rains or otherwise more slippery road conditions the rear will lose traction before the front and you'll find yourself in the same situation.

s2soonap1

yeah I plan on buying the rear sway bar, but I cant find where to buy the CR oem. I thought summer tires performed better in the rain than all seasons? and the car is not a daily so it would only be driven in light rain at most

114_ap2

If anything I'd change there rear sway to a ap2 rear and just get matching front and rear tires with the size you mentioned. This should be all you need

ZDan

1. What tires are on the car now? Make/model, age (week/year of production is on the sidewall), tread depth remaining.
2. What alignment settings? A ton of rear toe-in will make the car very twitchy over bumps.
3. Driving: if the back end of this car starts to come around when you're somewhat on the gas, and you LIFT off the gas, that will encourage it to spin.

I don't think you will need to change any hard parts to get the car handling properly.

rpg51

Helpful if you answer ZDan's questions. Also, is the suspension oem and in good shape?

But, I agree that first thing is to get good alignment and good tires before you start messing around with anything else. Those two things have a major impact on handling in general. My two ap1s do not have trouble like you describe at all. The cars are very well balanced. I had way out of date worn out tires on my 02 when I bought it and yes, it did behave a bit like you describe in the wet. But, once I got new tires and alignment all was well.

Was this incident you describe on wet roads?

Manga_Spawn

I asked the same questions. OP tell us what tires are on the car now and what their condition is. After that have an alignment done before buying anything.

cenix

The guys above are all spot on. Get your alignment checked/redone after you get new performance tires fitted. You may try to run more negative camber in the rear relative to the fronts.

sillyboybmxer

Were you in a turn when this happened? If its straight line where you hit bumps and it steps out, im thinking, cold temps, old/ hard tires, alignment, bad suspension (is it stock?)
sway bar isnt doing anything at "street" levels of driving

Orjinal

Did you expect an s2000 and especially an ap1 to handle like a boat? Coming from 135i to s2000, you need seat time to get used to its character.